docs: def _add_doc_value(self, field_name: str, jsonpath: str) -> None:
          """
          Add a value to knowledge graph by giving a jsonpath
  
          Args:
              field_name: str
              jsonpath: str
  
          Returns:
          """
          path = self.origin_doc.etk.parse_json_path(jsonpath)
          matches = path.find(self.origin_doc.value)
          all_valid = True
          invalid = []
          for a_match in matches:
              # If the value is the empty string, we treat is a None.
              if a_match.value:
                  valid = self._add_value(field_name, a_match.value, provenance_path=str(a_match.full_path))
                  if not valid:
                      invalid.append(field_name + ":" + str(a_match.value))
                  all_valid = all_valid and valid
  
          if not all_valid:
              raise KgValueError("Some kg value type invalid according to schema: " + json.dumps(invalid))